As Democratic Rep. Joaquin Castro mulls a challenge to Texas Sen. Ted Cruz, Democrats and Republicans both say it would be a tall order in a deep-red state with little Democratic power.

“I think what Joaquin would have to do right is to begin with a premise that Texas Democrats have no idea how to run a statewide race,” said Colin Strother, who has worked on campaigns for Castro and his twin brother Julian, a former Housing and Urban Development secretary and San Antonio mayor.

“The trick is that Democrats can win if we get turnout. You are not going to do that with TV and radio,” Strother said. “The way you do it is through a state of the art, modern, professional field program.”

For years, Democrats have been preaching that Texas would soon be theirs for the taking as demographics shift toward Democratic-leaning Latinos: Nearly one in five Hispanics nationwide live in Texas, according to the Pew Research Center. A report from January 2016 put the state’s eligible Hispanic voters at 4.8 million, surpassed only by California.

Furthermore, according to the U.S. Census Bureau, 39 percent of the Lone Star State’s population is Hispanic.

But recent Democratic efforts to win statewide races in Texas have fallen flat.

Texas Democrats have not won a statewide election since 1994, the same year George W. Bush unseated Democrat Ann Richards to become governor.

And banking on a lagging Cruz would not be a sound strategy, experts say. While the first-term GOP senator has developed a reputation of being disliked by some fellow Republicans — Arizona Sen. John McCain famously called Cruz and his allies “wacko birds” — he still has plenty of political support in Texas.

“Cruz is nothing if not calculating and he has a voracious appetite for politics,” Strother said, pointing to his 2012 upset win over Lt. Gov. David Dewhurst in the Republican Senate primary when Dewhurst had the support of Rick Perry, the state’s governor at the time.

Last year, Cruz faced some political headwinds after he refused to endorse Donald Trump, a bitter rival in the GOP presidential primaries, at the Republican National Convention, though he would endorse him in September. In 2014, he did not endorse fellow Texas Sen. John Cornyn in the Republican primary contest. Cornyn, in turn, did not endorse Cruz during his presidential run.

But the two senators have since “buried the hatchet,” said Jeff Roe, who served as Cruz’s campaign manager for his presidential run.

A University of Texas/Texas Tribune poll from last October showed that only 34 percent of Texans approved of Cruz’s job performance while 34 percent strongly disapproved and 11 percent somewhat disapproved.

But a UT/Texas Tribune poll released last month showed his approval numbers had improved slightly to 38 percent with 29 percent strongly disapproving and 10 percent disapproving somewhat.

And Cruz’s endorsement of Trump also seems to have staved off a potential primary challenge by Rep. Michael McCaul.

“Cruz is now in better shape since he has made detente with President Trump,” said Mark McKinnon, a political consultant who worked on Bush’s presidential campaigns. “You’re not hearing much about a Republican primary challenge like there was six months ago.”

And it is likely that Castro could face a Democratic primary challenge from Rep. Beto O’Rourke, who represents a district encompassing El Paso, along the border with Mexico.

“You have Beto who is from this border district,” said a Democratic source familiar with the race. “He represents the district pretty well over an issue that splits a lot of Americans.”

Strother said the best way to challenge Cruz on issues like Trump’s proposed Mexican border wall would be to localize it.

“What it has to be about is what Trump has to do this wall, which is spend billions of billions of federal taxpayers dollars on a boondoggle,” Strother said. “He’s going to be taking family ranches. He’s going to be taking little old ladies’ front porches from them.”

But Roe, Cruz’s presidential campaign manager, isn’t too worried about a challenge to the incumbent.

“Do they think he’s vulnerable?” he asked.

To be a viable challenger, Roe said, the challenge would have to come from a self-funder or a businessman.

But in the deep-red Lone Star State, Roe said Cruz is well-positioned, no matter what happens in the White House.